The words capital and capitol are near-homophones: they sound almost the same but have different
meanings.

Definitions

The noun capital has
multiple definitions: (1) a city that serves as the seat of government;
(2) wealth in the form of money or property; (3) an asset or advantage; (4) a capital letter (the type of upper-case letter used at the
beginning of a sentence).

As an adjective, capital refers to punishment by death
(as in "a capital offense") or a letter of the alphabet (in
the form A, B, C rather than a, b, c).

The adjective capital can also mean excellent or highly important.

The noun capitol refers to the
building in which a legislative assembly meets. (Remember that the o
in capitol is like the o in the dome of a capitol building.)

Examples

The dome
of the United States Capitol is
one of the most famous man-made landmarks in America.

The capital of Alaska is
Juneau.

"Hartford
[Connecticut] had always struck him as a pleasantly hick city, a
small forest of green-glass skyscrapers on the winding road to New York;
when you descended out of the spaghetti of overpasses, there was
a touching emptiness, of deserted after-hours streets and of a state capital's grandiose
vacancies."
(John Updike, "Grandparenting." The Maples Stories. Knopf, 2009)

"He
began to dust off the top and there found all sorts of things—a
forgotten pin box, a pill box with tacks in it, two knitting needles, and
an out-of-date diary on which was written in capitals: THE AIDEN
CYCLE."
(Christina Stead, The
Man Who Loved Children, 1940)

"It
is a capital mistake to
theorize before one has data. Insensibly one begins to twist facts to
suit theories, instead of theories to suit facts."
(Arthur Conan Doyle, "A Scandal in Bohemia," 1891)

"Though
many think capital
punishment is not an effective deterrent to crime, others insist this
is because criminals in the United States know they are not likely to
be convicted of a capital
crime and that if they are convicted, they are even less likely to be
executed."
(John S. Feinberg and Paul D. Feinberg, Ethics
for a Brave New World, 2nd ed. Crossway, 2010)

Practice

(a) The United States _____ building is located in Washington, D.C.,
the _____ city of the U.S.
(b) "We lived with our grandmother and uncle in the rear of the Store
(it was always spoken of with a _____ S), which she had
owned some twenty-five years."
(Maya Angelou, I Know Why the Caged Bird Sings. Random House,
1969)
(c) "[T]hecost of starting a boardinghouse in
San Francisco could be prohibitive, and very few newcomers to the West had the
_____ to open the kind of establishment that Pleasant financed on Washington
Street."
(Lynn Maria Hudson, The Making of "Mammy Pleasant": A Black
Entrepreneur in Nineteenth-Century San Francisco. University of Illinois
Press, 2003)Answers to Practice Exercises: Capital and Capitol(a) The United States Capitol building is
located in Washington, D.C., the capital city of the
U.S.
(b) "We lived with our grandmother and uncle in the rear of the
Store (it was always spoken of with a capital ​S),
which she had owned some twenty-five years."
(Maya Angelou, I Know Why the Caged Bird Sings. Random House,
1969)
(c) "[T]hecost of starting a
boardinghouse in San Francisco could be prohibitive, and very few
newcomers to the West had the capital to open the
kind of establishment that Pleasant financed on Washington Street."
(Lynn Maria Hudson, The Making of "Mammy Pleasant": A Black
Entrepreneur in Nineteenth-Century San Francisco; University of Illinois
Press, 2003)